`org.threeten.bp` gets generated even with `includeTTBP = false`

[j-mie6]

The includeTTBP flag stops SBT from seeing the org/threeten/bp/zone/TzdbZoneRulesProvider.scala file, but Metals will still see it and complain about it. Is it possible to instead avoid generating the file to begin with when the flag is off?

[cquiroz]

That sounds right, we should do that